This invention relates to the shuttle car disclosed by the Curry application Ser. No. 640,548 filed Dec. 15, 1975. That shuttle car comprises a tractor, a load-carrying trailer and a swivel interconnecting the tractor and trailer and positioned so that each can horizontally turn through a range of angularities relative to each other, the tractor and trailer each having a set of two wheels only, so that they can respectively pivot on the wheels. One or both sets of the wheels are reversibly powered and steering means are provided for controlling the angularities of the tractor and trailer, to steer the shuttle car.
Both the tractor and trailer have a low profile so the shuttle car can run forwardly and reversely through a mine haulway and into and from a mine crosscut, permitting the shuttle car to be parked in a mine crosscut to permit passage of a second one of the shuttle cars going through the haulway.
The tractor must carry expensive equipment such as the torque-responsive reel, which reels in and pays out the electric cable through which the car is electrically powered along with a reversing electric motor for powering the car's wheel sets, necessarily through reduction and differential gearing, and other equipment, anyone of which can be damaged by rocks, coal and the like, in large pieces falling from the mine roof on the tractor. Therefore, the top of the tractor is formed by a thick steel plate construction adequate to resist the shock of such falling pieces as experience has shown might be encountered in a mine.
However, for the operator of the car, the tractor is provided with an open-top cockpit which extends transversely with respect to the tractor for about half the latter's width and in which the operator sits transversely with his head above the tractor top so that by turning his head he can look forwardly when the car is running forwardly and backwardly when the car is running reversely. Although the operator can duck when approaching an unusually low mine roof, he is exposed directly to falling coal, rock and the like.
An object of the present invention is to provide the shuttle car operator with overhead protection providing a redundancy of safety that is at least equal to that provided for the components of the shuttle car.